Search Results (92)

Nano-titanium dioxide (nano-TiO₂) can alleviate oxidative damage in plants subjected to abiotic stress, interfere with related gene expression, and change metabolite content. Polylactic acid (PLA) microplastics can inhibit plant growth, induce oxidative stress in plant cells, and alter the biophysical properties of rhizosphere soil. In this study, untargeted metabolomics (LC-MS) and RNA-seq sequencing were performed on radish root cells exposed to nano-TiO₂ and PLA. The results showed that nano-TiO₂ alleviated the growth inhibition of radish roots induced by PLA. Nano-TiO₂ alleviated PLA-induced oxidative stress, and the activities of SOD and POD were decreased by 28.6% and 36.0%, respectively. A total of 1673 differentially expressed genes (DEGs, 844 upregulated genes, and 829 downregulated genes) were detected by transcriptome analysis. Metabolomics analysis showed that 5041 differential metabolites were involved; they mainly include terpenoids, fatty acids, alkaloids, shikimic acid, and phenylpropionic acid. Among them, phenylpropanoid biosynthesis as well as flavone and flavonol biosynthesis were the key metabolic pathways. This study demonstrates that nano-TiO₂ mitigates PLA phytotoxicity in radish via transcriptional and metabolic reprogramming of phenylpropanoid biosynthesis. These findings provide important references for enhancing crop resilience against pollutants and underscore the need for ecological risk assessment of co-existing novel pollutants in agriculture. Full article

Flavonoids play a crucial role in plant development, resistance, and the pigmentation of fruits and flowers. This study aimed to uncover the mechanism of flavonoid biosynthesis and fruit coloring in muscadine grapes. Two muscadine genotypes (Paulk and Supreme) were investigated via metabolomic and transcriptomic analysis during three developmental stages (bunch closure, veraison stage, and ripening stage). A total of 314 flavonoids were identified, with flavones and flavonols being the primary constituents. The contents of many differentially accumulated metabolites (DAMs) were higher at the veraison stage. The total anthocyanin content was upregulated during berry development, with the dominant type of anthocyanidin-3,5-O-diglucoside. Proanthocyanins accumulated higher levels in the ripening stage of Paulk than Supreme. Transcriptomic analyses revealed that over 46% of the DEGs exhibited higher expression levels in the bunch closure stage. Moreover, phenylalanine ammonia-lyase (PAL), cinnamyl 4-hydroxylase (C4H), and coumaryl CoA ligase (4CL) genes were upregulated during berry development, suggesting they promote second metabolites biosynthesis. The upregulation of dihydroflavonol 4-reductase (DFR) and leucoanthocyanin reductase (LAR) may related to the higher levels of PA in Paulk. Anthocyanidin synthase (ANS) and UDP-glucose:flavonoid-3-O-glucosyltransferase (UFGT) showed higher expression levels in the ripening stage, which may relate to the accumulation of anthocyanidins. This study provides comprehensive insights into flavonoid metabolism and berry coloration in Vitis rotundifolia. Full article

After being subjected to mechanical damage, plants trigger changes in primary and secondary metabolites to enhance their resistance or defenses. However, there are limited studies on the joint use of transcriptomics and metabolomics in investigating leaf damage-related defense mechanisms and their regulation in woody plants. This study investigated the leaf damage defense mechanisms of Populus talassica × Populus euphratica at the molecular level using transcriptome and secondary metabolome analyses. In total, 4078 differentially expressed genes (DEGs; 1207 up-regulated and 2871 down-regulated) and 30 differential secondary metabolites (DSMs; 21 up-regulated and nine down-regulated) were identified from a transcriptome analysis of controls (CK) and CL₇₅-treated leaves after 24 h. Plant–pathogen interactions and the MAPK signaling pathway were important defense pathways that synergized in the early stages of leaf damage in P. talassica × P. euphratica. There were 44 DEGs enriched in the KEGG pathways that encoded 21 WRKY transcription factors. Flavonoid genes were the most abundant. They were mainly enriched in the flavone and flavonol biosynthesis and flavonoid biosynthesis pathways. Sakuranetin and pinocembrin were most frequently associated with the differential metabolites and may be the main flavonoids involved in responding to leaf damage in P. talassica × P. euphratica. This study has far-reaching theoretical and practical significance for understanding the response strategies of P. talassica × P. euphratica to leaf damage and for achieving sustainable management and accurate predictions of artificial forests. Full article

Flavonoids are a class of secondary metabolites synthesized by plants, characterized by a C6-C3-C6 carbon skeleton and derived from the phenylpropane metabolism pathway. They play crucial biological roles, not only in plant pigment production and responses to biotic and abiotic stresses but also in medicinal applications. Consequently, the biosynthesis and regulatory mechanisms of flavonoids have been a focal point in plant transcription and gene expression research. The biosynthetic pathways of flavonoids include branches such as isoflavones, flavones, flavonols, anthocyanins, and proanthocyanidins, with some pathways and key enzymes already well-characterized. Studies indicate that plant flavonoids are regulated by various factors, including transcription factors, non-coding endogenous small RNAs (miRNAs), and plant hormones. This review systematically summarizes the structure and classification of plant flavonoids, their biosynthetic and regulatory mechanisms, and the factors influencing flavonoid synthesis. By discussing the regulation of flavonoid-related gene expression in plants, this work provides valuable insights and a theoretical foundation for future research and applications of flavonoids. Full article

Chrysanthemum indicum L. is characterized by a high concentration of flavonoid compounds, which exert multifaceted influences on the organoleptic properties, chromatic stability, and therapeutic efficacy of capitulum-derived extracts. These components exhibit diverse biological activities, including heat-clearing, antibacterial, and hepatoprotective properties. A novel white C. indicum variant lacking linarin was recently identified, but its metabolic and transcriptional differences from traditional yellow varieties remain unclear. This study compared flavonoid metabolism in white mutant (BHYJ) and yellow (HJ06) varieties through integrated metabolomic and transcriptomic analyses. Metabolomics identified 491 flavonoids, revealing distinct accumulation patterns: BHYJ accumulated dihydroflavones/chalcones (eriodictyol, hesperetin-8-C-glucoside-3′-O-glucoside, naringenin chalcone), while HJ06 showed higher flavones/flavonols (linarin, rhoiflolin, vitexin, rutin, nicotiflorin). Transcriptomics identified 43 differentially expressed enzyme genes, with key regulators FNSII, F3′H, and F3H showing expression patterns correlating with metabolite profiles. Integrated analysis revealed metabolic divergence at the naringenin node: BHYJ produced less naringenin than HJ06 and preferentially channeled it toward eriodictyol synthesis rather than linarin production. This metabolic shift explains the reduced linarin accumulation in BHYJ. Experimental validation confirmed the coordinated expression patterns of key enzymes. These findings provide foundational insights into transcriptional regulation of flavonoid divergence in pigmented C. indicum varieties, establishing a framework for elucidating enzymatic control of flavonoid biosynthesis in capitulum development. Full article

Mesona chinensis Benth is a significant botanical resource utilized for both medicinal and dietary purposes, and the Xiaoye variety (XY) exhibited the highest antioxidant activity among the varieties. Despite its importance, metabolic information regarding its medicinal and nutritional properties remains sparse. This study examined the secondary metabolites of four M. chinensis Benth varieties using UHPLC-MS/MS and identified 102, 105, and 286 metabolites exhibiting differential accumulation in the XY variety compared to the Taiwan variety (TW), Minxuan variety (MX), and Zengcheng variety (ZC), respectively, among the 1287 metabolites identified. These metabolites are predominantly involved in secondary metabolic pathways such as “Tropane, Piperidine, and Pyridine Alkaloid Biosynthesis” and “Flavone and Flavonol Biosynthesis”. In addition, we identified the ten most significant differential metabolites that influence antioxidant activity, with flavonoids recognized as the primary contributors to the variation in antioxidant activities. In this study, we have outlined the metabolic landscape of M. chinensis Benth. These findings may aid in elucidating the mechanism behind the antioxidant activity of XY, which provides valuable insights for breeding, quality assurance, and product innovation related to M. chinensis Benth. Full article

Solar radiation is crucial for intercropping, while partial shading can protect intercropped soybean leaves from irradiation damage during the pod-ripening period under high solar radiation. This study explored the leaf dynamics and soybean quality for the maize–soybean system, for monoculture soybean (MS), monoculture maize (MM), two-row maize + three-row soybean (IS2-3), and four-row maize + four-row soybean (IS4-4). The results revealed that soybean leaves under IS2-3 and IS4-4 treatments showed increases in Rubisco activity of 59.8% and 12.4% compared with MS, respectively. The antioxidant capacity in soybean leaves in MS was higher than that under intercropping treatments. Soybean leaves under IS2-3 and IS4-4 exhibited higher alpha and beta diversities in their endophytes compared with MS. The relative abundance of pathotrophs under IS2-3 was reduced by 19.1% and 22.6% compared to that of those under MS and IS4-4, respectively. The total land equivalent ratio (LER) under IS2-3 was more than 1.00, and increased by 6.4% and 15.7% compared with IS4-4 in 2023 and 2024, respectively. Soybean seeds under IS2-3 and IS4-4 showed 4.1% and 4.2% increases in crude protein content compared to those of MS, respectively. Among various biosynthesis and metabolism processes, flavone and flavonol biosynthesis exerted a stronger influence on soybean seeds in MS, IS2-3, and IS4-4. Soybean seeds under IS2-3 showed elevated genistein content and reduced daidzein content compared with those of MS. Intercropping soybean treatments, especially IS2-3, maintained leaf health during the pod-ripening period and enhanced the crude protein content compared with sole soybean treatment, thus guiding the design of intercropping in areas with high solar radiation. Full article

Nitrogen crucially impacts foxtail millet (Setaria italica) growth and development. Uncovering low nitrogen (LN) tolerance genes and mechanisms is vital for breeding high nitrogen use efficiency varieties. In this study, the LN tolerance of 50 foxtail millet genotypes was assessed through field trials and seedling hydroponic experiments. Subsequently, transcriptome analysis was performed on one highly sensitive genotype, named Maotigu, and on one highly tolerant genotype, named Dahuanggu, under LN (0.1 mmol/L) and control (5 mmol/L) conditions in seedling hydroponic experiments. Compared to the control treatment, 823 differentially expressed genes (DEGs) (350 upregulated, 473 downregulated) were identified in the roots of Dahuanggu, while 2427 DEGs (1703 upregulated, 724 downregulated) were detected in Maotigu under LN treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that a total of 3134 DEGs were associated with pathways including plant–pathogen interaction, amino sugar and nucleotide sugar metabolism, nitrogen metabolism, and others. A total of 116 DEGs were commonly identified between Dahuanggu and Maotigu, involving pathways like plant–pathogen interaction, galactose metabolism, and flavone and flavonol biosynthesis. The 28 of 116 DEGs showed opposite expression patterns between Dahuanggu and Maotigu; the expression of 18 genes was further validated using qRT-PCR. These offer valuable insights into the molecular mechanisms underlying LN stress responses in foxtail millet. Full article

Panax quinquefolius is a globally valued medicinal plant rich in bioactive flavonoids, yet the molecular mechanisms underlying their biosynthesis remain poorly understood. In this study, we integrated transcriptomic and metabolomic analyses to investigate tissue-specific flavonoid accumulation and regulatory networks in roots, leaves, and flowers. Metabolomic profiling identified 141 flavonoid metabolites, with flavones, flavonols, and C-glycosylflavones predominantly enriched in aerial tissues (leaves and flowers), while specific glycosides like tricin 7-O-acetylglucoside showed root-specific accumulation. Transcriptome sequencing revealed 15,551–18,946 DEGs across tissues, and the reliability of the transcriptomic data was validated by qRT-PCR. KEGG and GO annotation analyses suggested that these DEGs may play a crucial role in the biosynthesis and metabolism of secondary metabolites. From the DEGs, UGTs and MYB TFs were identified and subjected to correlation analysis. Functional validation through in vitro enzymatic assays confirmed that PqUGT71A1 catalyzes apigenin and naringenin glycosylation at the 7-OH position. Additionally, subcellular localization and yeast one-hybrid assays demonstrated that PqMYB7 and PqMYB13 interact with the PqUGT71A1 promoter and activate its expression.. This study unveils the spatial dynamics of flavonoid metabolism in P. quinquefolius and establishes a MYB-UGT regulatory axis, providing critical insights for metabolic engineering and bioactive compound optimization in medicinal plants. Full article

Broussonetia papyrifera is a deciduous tree with significant economic and medicinal value. It demonstrates notable physiological adaptability to mining areas with severe manganese contamination and is a pioneering species in the field of ecological restoration. Flavonoids are vital secondary metabolites that improve plant resilience to environmental stresses. In the study presented herein, immature and mature fruits of B. papyrifera grown in normal and high manganese environments were used as the test materials. B. papyrifera fruit was subjected to transcriptome sequencing via high-throughput sequencing technology to analyze its flavonoid metabolic pathways and related genes. Transcriptome sequencing identified a total of 46,072 unigenes, with an average length of 1248 bp and a percentage of Q30 bases ranging from 92.45 to 93.17%. Furthermore, 31,792 unigenes (69% of the total) were annotated using eight databases, including the GO and KEGG. Analysis of KEGG metabolic pathways and flavonoid content trends in B. papyrifera fruits revealed four unigenes with strong links to the flavonoid biosynthesis pathway under manganese stress: flavone 3-hydroxylase, flavonoids 3′,5′-O-methyltransferase, chalcone synthase, and flavonol synthase. These unigenes may play important roles in regulating flavonoid synthesis in B. papyrifera fruits under manganese stress. This study lays the groundwork for functional gene research in B. papyrifera. Full article

Background/Objectives: Bupleuri Radix is a plant in the Apiaceae family Bupleurum Chinense DC. or Bupleurum scorzonerifolium Willd. root. The dissimilarities in the metabolite profiles of plants directly correlate with the disparities in their clinical efficacy. Methods: Therefore, the wild Bupleurum Chinense DC. (YBC) and wild Bupleurum scorzonerifolium Willd. (YNC) were used as research materials. They were analyzed using the UPLC-MS/MS and the similarities and differences were uncovered based on differential metabolites. Results: Our results proved that the differences in clinical efficacy between YBC and YNC may be attributed to their distinct metabolite profiles, as follows: (1) a total of 12 classes of 2059 metabolites were identified in the roots, with phenolic acids, terpenoids, and flavonoids being the most abundant metabolic products, with 2026 shared components between the two, 2045 in YBC, and 2040 in YNC; (2) a total of 718 differential metabolites were identified, accounting for 35.44% of the shared metabolites. Among them, YBC had 452 metabolites with higher content relative to YNC, representing 62.95%, and 266 components with lower content, representing 37.05%; (3) the KEEG enrichment analysis results show that the differential metabolic pathways are flavone and flavonol biosynthesis, linoleic acid metabolism, arachidonic acid metabolism, sesquiterpenoid and triterpenoid biosynthesis, and linolenic acid metabolism. Conclusions: These new findings will serve as a foundation for further study of the BR biosynthetic pathway and offer insights into the practical use of traditional Chinese medicine in clinical settings. Full article

Italian ryegrass is a high-quality forage grass, and a full understanding of the changes in its microbiome and metabolome during aerobic exposure can prolong its aerobic stability and improve its utilization value. Italian ryegrass silage was prepared with deionized water (CK), Lactobacillus rhamnosus BDy3-10 (LR), Lactobacillus buchneri TSy1-3 (LB), and a mixture of these two lactic acid bacteria (M). The silage was maintained at ambient temperature for 60 days followed by aerobic exposure. The results show that the Italian ryegrass silage in the LB and M groups exhibited aerobic stability for up to 19 days. A total of 1881 chemicals were identified in Italian ryegrass silage. These metabolites are associated with bacterial communities, especially Lactobacillus. The addition of lactic acid bacteria resulted in a common differential metabolic pathway compared to CK: “phenylpropanoid biosynthesis”. “Flavone and flavonol biosynthesis” was the significant differential metabolic pathway between LB and LR. Inoculation with LB significantly increased the concentrations of lactic acid, acetic acid, vitexin, and luteolin. In conclusion, lactic acid bacteria (LAB) additives affect the microbial community and metabolites of silage. The application of LB inoculants is a feasible way to obtain well-fermented Italian ryegrass silage and improve aerobic stability, even at higher moisture content levels. Full article

Long-term use of the global non-selective herbicide glyphosate for weed control has caused resistance in weeds. Overproducing of the target of glyphosate 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) is one of the resistance mechanisms in weeds. However, few studies have measured the effects on tolerance levels and metabolite content in model plant species overexpressing EPSPS from weeds. We assessed the resistance levels of transgenic Arabidopsis thaliana overexpressing EPSPS from Eleusine indica, and its effects on metabolite content using the method of both quasi-targeted and targeted metabolomics. The results showed that the average resistance index of the transgenic lines was 4.7 and the exogenous E. indica EPSPS expression levels were 265.3- to 532.0-fold higher than those in the wild-type (WT) line. The EPSPS protein ranged from 148.5 to 286.2 μg g⁻¹, which was substantially higher than that in the WT line (9.1 μg g⁻¹). 103 metabolites associated with flavone and flavonol biosynthesis, the metabolism of aromatic amino acids, energy metabolism, and auxin synthesis were significantly higher in the transgenic glyphosate-resistant individuals (R) than in the WT individuals. The results of quantitative analysis show that pyruvate, sedoheptulose 7-phosphate, and gluconic acid amounts in R plants were 1.1-, 1.6- and 1.3-fold higher than those in WT plants, respectively. However, both citric and glyceric acid levels were 0.9-fold lower than those in WT plants. The abundance of other metabolites in the glycolytic and pentose phosphate pathways of central carbon metabolism was similar in the WT and transgenic plants. Glutamic acid was significantly more abundant in the transgenic line than in the WT plants. In contrast, asparagine, glutamine, and lysine were less abundant. However, the concentration of other amino acids did not change significantly. Overexpression of E. indica EPSPS in A. thaliana conferred a moderate level of tolerance to glyphosate. Metabolites associated with flavone and flavonol biosynthesis, the metabolism of aromatic amino acids, and energy metabolism were significantly increased. The results of this study will be useful for evaluating the characterisation and risk assessment of transgenic plants, including identification of unintended effects of the respective transgenic modifications. Full article

Dendrobium devonianum is an important medicinal plant, rich in flavonoid, with various pharmacological activities such as stomachic and antioxidant properties. In this study, we integrated metabolome and transcriptome analyses to reveal metabolite and gene expression profiles of D. devonianum, both green (GDd) and purple-red (RDd) of semi-annual and annual stems. A total of 244 flavonoid metabolites, mainly flavones and flavonols, were identified and annotated. Cyanidin and delphinidin were the major anthocyanidins, with cyanidin-3-O-(6″-O-p-Coumaroyl) glucoside and delphinidin-3-O-(6″-O-p-coumaroyl) glucoside being the highest relative content in the RDd. Differential metabolites were significantly enriched, mainly in flavonoid biosynthesis, anthocyanin biosynthesis, and flavone and flavonol biosynthesis pathways. Transcriptomic analysis revealed that high expression levels of structural genes for flavonoid and anthocyanin biosynthesis were the main reasons for color changes in D. devonianum stems. Based on correlation analysis and weighted gene co-expression network analysis (WGCNA) analysis, CHS2 (chalcone synthase) and UGT77B2 (anthocyanidin 3-O-glucosyltransferase) were identified as important candidate genes involved in stem pigmentation. In addition, key transcription factors (TFs), including three bHLH (bHLH3, bHLH4, bHLH5) and two MYB (MYB1, MYB2), which may be involved in the regulation of flavonoid biosynthesis, were identified. This study provides new perspectives on D. devonianum efficacy components and the Dendrobium flavonoids and stem color regulation. Full article

Grafting technology can improve the yield and quality of crops. In this study, we investigated the effects of grafting on watermelon using transcriptomic and metabolomic analysis. A total of 216 differentially accumulated metabolites (DAMs) were identified between pumpkin-grafted watermelon and self-grafted watermelon. KO (Kyoto Encyclopedia of Genes and Genomes Orthology) analysis revealed that the DAMs were mainly enriched in the flavone and flavonol biosynthesis pathway. In addition, high levels of phloretin and citric acid were found in pumpkin-grafted watermelon, which contributes to fruit quality. Meanwhile, compounds such as olivetol and ferulaldehyde, which confer a bitter taste, were downregulated in pumpkin-grafted watermelon. The transcriptome data indicated that the differentially expressed genes (DEGs) identified in the pulp were enriched in fructose and mannose metabolism, biosynthesis of secondary metabolites, and flavone and flavonol biosynthesis pathways. Moreover, genes related to the microtubule, cell wall, and fiber were highly expressed in the stem of pumpkin-grafted watermelon, suggesting that grafting could change the structure of the stem and improve the quality of watermelon fruit. Our study provides a comprehensive picture of the transcriptional and metabolic profile of watermelon induced by grafting, which furthers our understanding of the molecular mechanisms involved in improving watermelon fruit quality by grafting. Full article